[Chromisdesigns]

A guy I've been trading posts with in the Craigslist electronics forum is a keyboards player ala Emerson Lake and Palmer, Yes, etc. and wants some serious bottom octave grunt from his setup.  According to him, most pro audio gear rolls off badly below about 40 hz (lowest string on bass guitar) and this severely limits the synth-heavy sounds.

He's thinking about designing and building his own cab(s), seems to have a reasonable handle on how to design them and the limiting factors at those frequencies and levels.  I found a couple of hifi manufacturers claiming to be able to do it -- Axiom and Definitive Tech (their "SuperCube Trinity" product).

Any other suggestions from the bass-happy crowd here?  He knows DIY isn't going to be either cheap or easy!

[DaveC113]

I have a 6 string bass guitar and I use a Carvin 18" cabinet as a subwoofer. Good to the mid to high 20 Hz range and the price isn't that bad. I'm sure there are options that will get down to 20, but I'd bet it won't be cheap.

[JohnR]

I don't have anything like that, but a couple of ported 15's looks like it would do it. Did he say where (and why?) he wants 120 dB - in the audience or at 1m?

[Chromisdesigns]

I have a 6 string bass guitar and I use a Carvin 18" cabinet as a subwoofer. Good to the mid to high 20 Hz range and the price isn't that bad. I'm sure there are options that will get down to 20, but I'd bet it won't be cheap.

He's got plenty of options that will give him flat response to 20 hz, his problem is he can't get enough output from them.  I jokingly suggested he try Nelson Pass's "El Pipe-O" design, and this was his response:

"Pretty funny!  I could probably fold the tubes and do it. But even Pass' big design with 4 woofers calculates to only 115dB at woofer burn-out. I did some t-line calculations and drew the same conclusion.  The only way to increase a woofer's response more than 6dB below Fs is a horn and that only if you have a woofer really designed for horn-loading (low Q - approx 0.2). Then, the horn's gonna be BIG - half wave across at the mouth! 55 feet. Length should be 5-10 times the mouth opening!"

He appears to know his way around the design parameters, but I'm still not sure why he needs such high levels.

[Chromisdesigns]

I don't have anything like that, but a couple of ported 15's looks like it would do it. Did he say where (and why?) he wants 120 dB - in the audience or at 1m?

At 1 meter.  God help the audience if he puts those things at the front of the stage!

[medium jim]

At 1 meter.  God help the audience if he puts those things at the front of the stage!

Can you say Ear Plugs!

Jim

[DaveC113]

I agree with ported 15s, Hsu is making a sub that goes down to 15 Hz, -1 dB...  enough of them should hit 120 dB. 

http://www.hsuresearch.com/products/uls-15.html

I can understand why he wants that much bass, synths can go as low as you want them to and low bass makes for some cool effects in live shows. The Ogden in Denver has a system that makes clothing move in time to the music...  I just saw Beats Antique at Red Rocks, check out Elektrafone, it's got some nice synth bass lines.

[medium jim]

For keyboards, go with a Leslie, especially with a Hammond B3. A Leslie will go as low as you want and we blow easily at 120db.

The Leslie model 147 can be used for practically any organ/keyboard if you aren't using a Hammond.
Jim

[John Casler]

Danley DTS20

[Scott F.]

Danley DTS20

I need a pair of hose for my listening room 

[Chromisdesigns]

Looks like he's got it in hand -- going to do a one-off based on the "Trinity" -- here's his latest post, after I suggested finding one and trying it, given what he's likely to have in it for parts alone, by the time he's done:

"...re the Trinity:

I need something that can be hauled around, suspended on rigging, placed on stands (standard 35mm commercial PA mount), etc. Home gear isn't pro gear...it sounds better, but it's not set up to integrate into a stage setup.

Part of the Trinity's cost is the finish. I'll be using cheap Tolex. Pro speakers are made of Baltic Birch, not MDF...for weight savings. You make some acoustic tradeoffs in exchange for portability.

I've actually got drivers lined up - a pair of 15s, modded by the manufacturer for lower Fs. If I port the cab at 18Hz, then institute a sharp cut-off below 20Hz, I'll have well controlled cone motion. I calculate 115dB at 20Hz in a large room at 1kW (the drivers can take 2.4kW for the pair). I'll start there. I like analog devices' class D amp chips, the rest is fairly straightforward on the amp. I'd use Linkwitz-Riley 8th order xover to the next-up woofers, then 4th order Linwitz-Riley to the "rest of the setup", which would have passive xovers between midbass, mid and highs. The system has to be integrated, acoustically.

I'll probably end up with $4k into it when I'm done, but heck...my acoustic piano cost 8X that much, so I'm acclimated to paying for my instruments."

Thanks for the suggestions, everyone.  Hope he eventually posts back with results.

[Vingard]

This show... I must attend!

[Wayner]

Tell me which key on the keyboard plays a 20hz note?

If the instrument doesn't have the capability to produce that tone,
what is the point?

Wayner

[Chromisdesigns]

Tell me which key on the keyboard plays a 20hz note?

If the instrument doesn't have the capability to produce that tone,
what is the point?

Wayner

You can program a synth to play any frequency you want, within its capability.  The lowest note on a full pipe organ is 16 hz.

[*Scotty*]

Wayner, there's a wiki for that. See links below.
http://en.wikipedia.org/wiki/Musical_keyboard
welve_and_eight_equal_tempered_scale.jp g" class="bbc_link" target="_blank" rel="noopener noreferrer">http://en.wikipedia.org/wiki/File:Frequencies_of_the_audible_range_on_a_t welve_and_eight_equal_tempered_scale.jp g
Depending on the room/venue volume, I would start with an 18inch driver,possibly 2 drivers. Even a small club will suck up low frequencies very quickly. I would also want to buy a driver from a vendor that will guarantee a minimum of 120dB SPL at 20Hz in a recommended enclosure design. It would be better to have a solid 16Hz extension,that's B-1.
Scotty

[kevin360]

Having a pair of Definitive's SuperCube Reference subs in my listening room, I can vouch for their ability to produce deep notes authoritatively. I can only imagine what the Trinity can do. It was actually designed to act as the bottom end of a 'proper' church organ (but the OP has surely read all of this). Their approach* works and can be confirmed by witnessing the denuded sub in action - the tuned radiators on each side move significantly more than the front firing driver when they reproduce really deep notes.

What's the point? The often cited range I see for the standard bass/keyboard is silly. Players have been able to extend that range with their feet for decades. When you hear it, you definitely get the point.

*Unless the device has a pair of tuned radiators (for the sympathetic behavior of the spring to act favorably, the system must be complete and mathematically correct), the principle of physics by which Definitive's design reproduces deep bass is not being employed.

[medium jim]

Having a pair of Definitive's SuperCube Reference subs in my listening room, I can vouch for their ability to produce deep notes authoritatively. I can only imagine what the Trinity can do. It was actually designed to act as the bottom end of a 'proper' church organ (but the OP has surely read all of this). Their approach* works and can be confirmed by witnessing the denuded sub in action - the tuned radiators on each side move significantly more than the front firing driver when they reproduce really deep notes.

What's the point? The often cited range I see for the standard bass/keyboard is silly. Players have been able to extend that range with their feet for decades. When you hear it, you definitely get the point.

*Unless the device has a pair of tuned radiators (for the sympathetic behavior of the spring to act favorably, the system must be complete and mathematically correct), the principle of physics by which Definitive's design reproduces deep bass is not being employed.

Precisely why I recommended the Leslie, which has been the standard for Touring Organs for well over 50 years...albeit, they're very large...if you've ever heard one live, you will know what I'm talking about.  While they're self powered, only about 40watts, they're very efficient and would dare to say over 100db eff. 

Just listen to the Allman Bros, Live at the Fillmore East and you will get a sense of how low they can go...or Virgil Fox playing Bach.

Jim

[bpape]

For low and loud, either look at Danley or Seaton.

Bryan

[Wayner]

You can program a synth to play any frequency you want, within its capability.  The lowest note on a full pipe organ is 16 hz.

My point was that producing such low tones at such
high volumes would have the band out in the back alley if it were my establishment (and gone forever).
The only ones enjoying such extreme-isms would be the band. So much effort for a non-musical event.

Enough said.

[DaveC113]

The only ones enjoying such extreme-isms would be the band. So much effort for a non-musical event.

Enough said.

I disagree. Loud bass used with taste can be a very cool effect and adds to the music. Sorry you have never experienced this.